#include	<stdio.h>
#include    <stdlib.h>
#include	<unistd.h>

#define	oops(m,x)	{ perror(m); exit(x); }

int main(int ac, char **av)
{
	int	thepipe[2],			
		newfd,				
		pid;				

	if ( ac != 3 ){
		fprintf(stderr, "usage: pipe cmd1 cmd2\n");
		exit(1);
	}
	if ( pipe( thepipe ) == -1 )		
		oops("Cannot get a pipe", 1);

	if ( (pid = fork()) == -1 )			
		oops("Cannot fork", 2);

	if ( pid > 0 ){			
		close(thepipe[1]);	

		if ( dup2(thepipe[0], 0) == -1 )
			oops("could not redirect stdin",3);

		close(thepipe[0]);	
		execlp( av[2], av[2], NULL);
		oops(av[2], 4);
	}

	close(thepipe[0]);		

	if ( dup2(thepipe[1], 1) == -1 )
		oops("could not redirect stdout", 4);

	close(thepipe[1]);		
	execlp( av[1], av[1], NULL);
	oops(av[1], 5);
}
